JPH10324007A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink jet printer which can be maintained quickly and surely while reducing the size and enhancing the print quality. SOLUTION: An ink jet nozzle 207 for each color is moved in the direction of orthogonal axis J2 and positioned selectively between a print position P1 and a nonprint position P2 so that printing and maintenance can be executed. An elevating means 300 elevates a slider 311 for supporting the ink jet nozzle 207 for each color along a guide rail 301 using electric power and a brake means 341 brakes natural fall of the slider 311 upon power interruption.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer capable of performing color printing by jetting ink from a color ink jet nozzle onto a printing surface.

[0002]

2. Description of the Related Art An ink jet printer prints characters, images, and the like by jetting (flying) ink from a fine ink jet nozzle equivalent to one dot. Clogging easily occurs. In particular, in an ink jet printer capable of color printing having ink jet nozzles for each color, the number of nozzles is larger than that for a single color ink jet printer, so that it is important to further prevent nozzle clogging and eliminate the clogging.

Therefore, in an ink jet printer, it is necessary to periodically maintain (clean) the ink jet nozzles.

[0004] As a maintenance method, a negative pressure suction method in which ink is suctioned from the tip of each nozzle using negative pressure, and ink is ejected by applying a higher pressure than usual to an ink pressure chamber common to each nozzle. There is a pressure discharge method,
A negative pressure suction system is often employed.

A general ink jet printer is shown in FIG.
As shown in the figure, a print head 500 which is integrated with an ink tank (ink cassette) 513 and has an inkjet nozzle for one dot in the row direction (X) of the print medium M and a plurality of dots in the column direction using a reciprocating means. And line direction (X)
And prints characters, images, and the like on the printing surface of the printing medium M by inkjet while reciprocating over the entire length of the printing medium M.

In such a serial type ink jet printer, when eliminating ink clogging of each ink jet nozzle, the print head 500 is largely moved in the row direction (X) of the print medium M to clear the print area. Then, in the empty area, ink is suctioned from each ink jet nozzle under a negative pressure using the maintenance means 530 (negative pressure suction tool 531, suction pump 535).

By the way, the above-mentioned conventional print head is reciprocated over the entire length in the line direction and is printed during each forward movement to print one line, and after printing one line, a printing medium [plain paper, plastic film ( OHP film), etc.]. Compared to a so-called serial type ink jet printer in which M is fed one line in the column direction and repeats these steps, the printing speed can be greatly increased and continuous printing operation can be performed over many sheets. The present applicant has proposed an ink jet printer that can be made much smaller than a laser printer (for example, Japanese Patent Application No. 8-296957).

That is, in FIG. 7, the rotating body (drum 10) is rotatable in one direction about the rotation axis and can hold the print medium M on the outer peripheral surface 11 thereof. A nozzle unit (print head) 200 for each color is disposed in the rotation (Y) direction of the drum 10.

Therefore, an integrated nozzle unit 200 for each color in the entire length in the row direction (the width direction of the printing surface, that is, the direction perpendicular to the paper surface in FIG. 7) or a plurality of nozzle unit elements arranged in the row direction for each color. Nozzle unit 200,
For example, ink is sprayed from the inkjet nozzles 207 for each color on the rotating print medium M while reciprocatingly moving by the pitch between the inkjet nozzles to print in the row direction, and the drum 1 is moved during the forward movement of the inkjet nozzle pitch.
Printing can be performed in the column direction while utilizing the rotation of 0.
That is, since the row-direction printing and the column-direction printing can proceed at the same time, the printing speed can be significantly increased.

Further, since the nozzle unit 200 for each color and the ink tank (ink cassette) 213 for each color are arranged at a distance from each other via a tube, the nozzle unit 200 for each color can be lightened and reciprocated in the row direction. The fact that the moving speed can be greatly increased also contributes to further increase in printing speed, and ink tanks (ink cassettes) 2 for each color.
13 can be greatly expanded, so that, for example, a continuous printing operation of 500 sheets or more can be performed.

In order to realize these, one side (right side in FIG. 7) of the drum 10 is provided with a feeding means 60 and a medium feeding means 9.
0, and on the other side (left side in FIG. 7), the medium peeling means 140, the medium discharge / conveyance means 160, and the direction switching means 190
Are provided.

The feeding means 60 can selectively feed the printing medium M one by one from one of the cassette feeding means 71 and the manual feeding means 61. The medium supply means 90 feeds the fed print medium M to the drum 1 at a predetermined timing.
Feed to the 0 side. The medium peeling means 140 peels the print medium M from the drum 10 after printing, and
0 discharges and conveys the peeled print medium M to the left in FIG. The direction switching unit 190 selectively switches between the discharge tray 192 and the upper discharge tray 193.

Thus, since the feeding, supply, holding, printing, peeling, and discharging and conveying of the printing medium M can be continuously performed, multicolor printing of, for example, 20 sheets or more of A4 size can be performed in one minute.

[0014]

In such an ink jet printer of the prior proposal, the print head (200) is moved to an empty area in the row direction similarly to the above-mentioned general ink jet printer (serial type ink jet printer). When performing maintenance, a large space enough to accommodate the long print head (200) in the row direction must be secured as the empty area, and the printer becomes large.

Further, the print head (200) must be largely moved in the row direction, and it is difficult to perform maintenance quickly. Further, the positioning accuracy of the print head (200) with respect to the printing surface is apt to decrease, and it is difficult to achieve high quality printing.

[0016] The above-mentioned inconvenience also occurs in a conventional line type ink jet printer having a long print head in the row direction. Further, even in a serial type ink jet printer, a similar problem occurs when, for example, an attempt is made to shorten the reciprocating movement time (shortening the printing time) by increasing the dimension of the print head in the row direction. .

An object of the present invention is to provide an ink jet printer capable of performing maintenance quickly and reliably while achieving downsizing and high quality printing.

[0018]

According to a first aspect of the present invention, an ink jet nozzle for each color is formed so as to be movable up and down between a printing position in a direction of an orthogonal axis orthogonal to a printing surface and a non-printing position by using a lifting means. And an inkjet printer formed so that the inkjet nozzles for each color can be printed on the printing surface as inkjets from the inkjet nozzles for each color at the printing position and the maintenance of the inkjet nozzles for each color can be performed at the non-printing position.

In the case of this invention, printing and maintenance can be performed by moving the ink jet nozzles for each color in the direction of the orthogonal axis to selectively position the printing position and the non-printing position.

Here, the moving direction of each color ink jet nozzle is different from the width direction (row direction) and the longitudinal direction (column direction) of the printing surface, and furthermore, the movement direction between the printing position and the non-printing position. The distance can be significantly reduced. Therefore, it is possible to quickly move from the printing position to the non-printing position and perform maintenance, and it is not necessary to secure a large empty space for maintenance in the width direction of the printing surface, and for each color when returning to the printing position. The relative positioning between the inkjet nozzle and the printing surface can also be accurately performed. As a result, the inkjet nozzles for each color can be quickly and reliably maintained while achieving downsizing and high quality printing.

According to a second aspect of the present invention, there is provided a guide rail, wherein the lifting means is parallel to the orthogonal axis and is erected on one side centered on the orthogonal axis in the longitudinal direction of the printing surface, and is movable up and down on the guide rail. A slider attached to the
An ink-jet printer comprising lifting means for driving the slider up and down using electric force, and brake means for suppressing the natural fall of the slider when the lifting drive means cannot be driven up and down due to a power failure. is there.

According to this invention, the position (printing position, non-printing position) of the ink jet nozzle for each color in the direction of the orthogonal axis (printing position, non-printing position) can be quickly and accurately switched by raising and lowering the slider using the lifting drive means utilizing electric force. Therefore, the maintenance can be performed quickly and reliably, and the printing can be executed quickly and accurately by returning to the printing position after the maintenance.

In the event of a power outage, the brake means
Since the natural fall of the slider is suppressed, it is possible to prevent the slider from rapidly falling and the inkjet nozzles for each color from being damaged by an excessive impact force.

Therefore, the same operation and effect as those of the first aspect of the invention can be obtained, and furthermore, the maintenance can be performed more quickly and smoothly, and the printing speed, the quality and the durability can be further improved.

According to a third aspect of the present invention, the ink jet nozzle for each color is rotatably mounted on the slider around a fulcrum, and engages with the slider, and resists the rotating power of the ink jet nozzle for each color due to its own weight. Further, the inkjet printer is provided with attitude stabilizing means for stabilizing the attitude of the ink jet nozzle for each color with respect to the guide rail.

In this invention, the attitude of the ink jet nozzle for each color with respect to the guide rail is kept constant by the attitude fixing means. Therefore, the spray condition of each color ink jet nozzle and the attitude at the time of maintenance are always kept constant, so that the same operation and effect as the case of the invention of claim 2 can be obtained, and further higher quality printing can be performed. Maintenance can be performed more smoothly and reliably.

According to a fourth aspect of the present invention, the lifting drive means is formed of a motor and a power conversion means for converting the rotational power of the motor into the lifting power of the slider, and the brake means is involved with the motor or the power conversion means. And a state switching means for switching the braking force applying means to a state in which the braking force cannot be applied by using the electric force and a state in which the braking force can be applied in the event of a power failure. Is an inkjet printer.

In the case of this invention, the lifting / lowering means uses a general motor as a power source for utilizing the electric force, and the braking force applying means uses the electric force to switch between the state where the braking force can be applied and the state where the braking force cannot be applied. Therefore, the same operation and effect as those of the inventions of claims 2 and 3 can be obtained, and the structure can be further simplified and the applicability can be expanded.

[0029]

Embodiments of the present invention will be described below with reference to the drawings. This inkjet printer is shown in FIG.
As shown in FIG. 5 to FIG. 5, the basic configuration is the same as that of the ink jet printer of the previous proposal (FIG. 7), except that a print head (nozzle unit 200 for each color), a maintenance means 230, and an elevating means 300 are provided. , Print head (20
0) the ink jet nozzle 207 for each color
The printing position P1 and the non-printing position P2 in the direction of the orthogonal axis (J2) orthogonal to the printing surface M1 are selectively positioned to enable printing and maintenance.

The same components as those of the previously proposed ink jet printer (FIG. 7) are denoted by the same reference numerals, and the description thereof will be simplified or omitted.

In this embodiment, the printing medium M (the printing surface M
1) is a rotating body (drum 10) that rotates in one direction (Y) about a rotation axis J1 as shown in FIGS.
And can be moved (rotated) in the longitudinal direction [rotational direction (Y) of the drum 10]. The orthogonal axis (J2) is the rotation axis (J
The vertical axis passes through 1).

The nozzle unit 200 for each color has a printing surface M
1 are displaced in the longitudinal direction (Y), and each nozzle unit 200 is formed from a number of inkjet nozzles 207 arranged in the width direction (X) of the printing surface M1.

In addition to the fact that the printing surface M1 is formed so as to be rotatable about the rotation axis J1, the ink jet nozzle 207 of each color nozzle unit 200 is
The ink outlets are arranged on a radial axis centered on a common point and on an arc locus corresponding to the printing surface M1.
For example, the arrangement order from the upstream side to the downstream side in the printing surface longitudinal direction (Y) is the nozzle unit 200 for cyan, magenta, yellow, and black.

Next, the lifting / lowering means 30 which is a feature of the present invention is described.
Reference numeral 0 denotes a guide rail 301 which is parallel to the orthogonal axis (J2) and stands on one side centered on the orthogonal axis (J2) in the longitudinal direction (Y) of the printing surface M1, and is capable of moving up and down on the guide rail 301. The slider 311 includes an attached slider 311 and an elevating drive unit 321 that drives the slider 311 up and down using electric force.

More specifically, the guide rail 301 is shown in FIG.
As shown in the figure, the fixed frame 309F is provided upright at both ends in the printing surface width direction (X). The slider 311 is
Both ends of the printing surface width direction (X) are connected to both guide rails 301.
It is supported to be able to move up and down. The slider 311 has an ink jet nozzle 207 for each color rotatable about a fulcrum (support shaft 315) via a nozzle support member 309 and a guide rail 301 using a posture stabilizing unit 331.
It is mounted so that the posture with respect to is constant.

The attitude stabilizing means 331 includes the slider 31
1 is a means for engaging the nozzles 1 with each other and stabilizing the attitude of each nozzle 207 with respect to the guide rail 301 against the rotational force of the ink jet nozzle 207 for each color due to its own weight.

More specifically, the attitude stabilizing means 331 includes a shaft member 332 attached to the slider 311 above the support shaft 315 in parallel with the support shaft 315, and a rotation support above the nozzle support member 309. And a roller 335 pressed against the shaft member 332. Roller 3
35 is pressed against the shaft member 332 by a rotating force due to the weight of the ink jet nozzle 207 for each color and the like.

The ink jet nozzle 207 for each color
Is reciprocated in the width direction (X) of the printing surface M1 by the reciprocating means 371 to perform line-direction printing. The reciprocating means 371 includes a cam 372 rotatably supported by a slider 311 and a cam driving means 373 (a driving motor 374, a gear power transmission mechanism 375, an engagement spring 37).
6), a cam follower 377 provided on the nozzle support member 309, and the like.

The lifting drive means 321 includes a motor 322,
And a power conversion means 323 for converting the rotational power of the motor 322 into the lifting power of the slider 311.

Specifically, the power conversion means 323 includes a rack and pinion mechanism 324 and a power transmission mechanism 327 and is formed. The rack and pinion mechanism 324
The rack 325 is formed to extend vertically and attached to the slider 311, and the pinion 326 is rotatably supported by the fixed frame 309 </ b> F and meshes with the rack 325.

The power transmission mechanism 327 includes the motor 32
Gears (G1, G1)
2, G3, G4), and is configured to be able to transmit the rotational power of the motor 322 to the pinion 326. Therefore, when the motor 322 is driven, the slider 311 moves up and down in the orthogonal axis direction.

Here, since the lifting / lowering means 300 raises / lowers the slider 311 using an electric force, the natural falling of the slider 311 is suppressed when the lifting / lowering driving means 321 cannot be driven up / down due to a power failure. Brake means 341 is provided.

The braking means 341 includes a braking force applying means 342 capable of applying a braking force in association with the motor 322 or the power converting means 323, and a braking force applying means 3
And state switching means 346 for switching to a state in which the braking force cannot be applied and a state in which the braking force can be applied in the event of a power failure.

The braking force applying means 342 is
3, a friction belt 344, and a biasing spring 345,
The motor 322 is formed to be able to apply a braking force using a frictional force. The friction wheel 343 is mounted on a rotating shaft of a motor 322, and a friction belt 344 is wound around the friction wheel 343. The upper end of the friction belt 344 is connected to the fixed frame 309F, and the lower end thereof is configured to be pulled downward by the biasing spring 345.

Therefore, the outer peripheral surface of the friction wheel 343 is strongly tightened by the friction belt 344 provided with tension by the biasing spring 345, and a large friction force is applied between the friction belt 344 and the friction wheel 343. Occur. That is, a braking force is applied to the motor 322 by friction.

The state switching means 346 includes a switching lever 347.
And a solenoid 348. The switching lever 347 is rotatably attached to the fixed frame 309F via a hinge portion. One end of the switching lever 347 is connected to the lower end of the friction belt 344, and the other end is connected to the rod 348R of the solenoid 348. Have been. When driven, the solenoid 348 causes the rod 348R to move downward against the urging force of the urging spring 345.

Therefore, when the power of the apparatus is turned on and the solenoid 348 is driven, the switching lever 34
7, the friction belt 344 is loosened and the belt 3
The frictional force generated between the friction wheel 44 and the friction wheel 343 is eliminated. That is, the braking force applied to the motor 322 disappears. At the time of a power failure, the solenoid 348 is in a non-drive state, and the friction wheel 343 is strongly tightened by the friction belt 344 by a spring force. That is,
A braking force is applied to the motor 322.

As shown in FIGS. 3 and 4, the maintenance means 230 moves the suction tool 231, the wiper 234 provided on the upper surface of the suction tool 231, and the suction tool 231 in the row direction (X) of the printing surface M 1. Movable suction tool moving means 23
5 is formed so as to be able to clean the inkjet nozzles 207 for each color while sucking ink from the inkjet nozzles 207 for each color while moving in the row direction during non-printing.

The suction tool 231 includes a main body 231D and a plurality of ink suction nozzles 23 radially disposed on the main body 231D in correspondence with the ink jet nozzles 207 for each color.
1N and the like. Each ink suction nozzle 2
31N is connected to a negative pressure generating means 233 through a pipe 232.
(Waste ink storage tank 233T, suction pump 233P)
Is connected.

Therefore, each ink suction nozzle 231
When the suction pump 233P is driven in a state where N is aligned with the tip of each ink jet nozzle 207, the ink in each ink jet nozzle 207 is discharged to the waste ink storage tank 23.
Collected in 3T. The suction tool 231 is provided with a wiper 234 capable of wiping ink adhering to the tip of each ink jet nozzle 207 immediately after cleaning.

The suction tool moving means 235 is shown in FIGS.
, A pair of guide members (guide rod 235G, guide bar 235B) and a pair of guide members (235G, 235B) disposed parallel to the rotation axis J1 of the drum 10.
Support member 235 whose both ends are movably supported by
S, and a belt transmission mechanism 235D that can move and drive the suction tool support member 235S. The suction tool 231 attached to the suction tool support member 235S can
1N is formed so as to be able to face the tip of each color inkjet nozzle 207 in a non-contact state. That is, the relative positions of the respective ink suction nozzles 231N and the respective color inkjet nozzles 207 are adjusted such that a minute gap is formed therebetween.

Next, the operation of this embodiment will be described. When performing maintenance (cleaning) of the inkjet nozzles 207 for each color, the motor 322 of the elevation drive means 321 is driven during non-printing to raise the slider 311 to position the inkjet nozzles 207 for each color at the non-printing position P2.

Next, the suction tool moving means 235 is driven to
The suction tool support member 235S is moved in the width direction of the printing surface M1 (X1)
To go to Then, each negative pressure suction unit (231N) sucks ink from the inkjet nozzle 207 for each color.

As described above, since the ink is suctioned from each of the ink jet nozzles 207 sequentially aligned with the negative pressure suction section (231N) with the forward movement of the slider, sufficient cleaning can be performed even if the negative pressure suction capacity is reduced. can do. Then, the ink can be sufficiently suctioned from the ink jet nozzle 207 which may be clogged with the ink, and the ink can be cleaned.

The maintenance means 230 wipes the remaining ink for each color while contacting the ink jet nozzles 207 with the elastic contact portions 234 after cleaning, so that the ink is hardened at the tip of each nozzle 207. Can be prevented. Therefore, all the nozzles 207
Can be uniformly and reliably maintained (cleaned), and the negative pressure suction ability can be reduced.

According to this embodiment, the ink jet nozzle 207 for each color is moved in the direction of the orthogonal axis (J2) to selectively position the printing position P1 and the non-printing position P2 so that printing and maintenance can be performed. Since it is formed, it is not necessary to secure a large empty space for maintenance in the width direction (X) of the printing surface M1, and the ink jet nozzle 207 for each color and the printing surface M1 when returning to the printing position P1 are not required. Relative positioning can also be performed accurately. As a result, the inkjet nozzles 207 for each color can be quickly and reliably maintained while achieving downsizing and high quality printing.

A slider 311 for supporting the ink jet nozzle 207 for each color is formed so as to be able to be driven up and down along the guide rail 301 by utilizing the electric force of the lifting / lowering means 300, and a brake for suppressing the natural fall of the slider 311 at the time of a power failure. Since the means 341 is provided, the slider 31
The position 1 (printing position P1, non-printing position P2) can be switched quickly and accurately. Also, at the time of power failure, the slider 311 rapidly drops and stops, and the inkjet nozzles 207 for each color are used.
Can be prevented from being damaged by an excessive impact force. Therefore, it is possible to achieve higher printing speed, higher quality, and higher durability.

Further, the ink jet nozzle 207 for each color is used.
Of the ink jet nozzle 207 for each color and the attitude during maintenance are always kept constant, so that maintenance can be performed smoothly and reliably. I can do it.

The lifting drive means 321 uses a general motor 322 as a power source for utilizing electric power, and the braking force applying means 342 uses electric force to switch between a state in which braking force can be applied and a state in which braking force cannot be applied. Therefore, the configuration can be further simplified and the applicability can be expanded.

[0060]

According to the first aspect of the present invention, the ink jet nozzle for each color is moved in the direction of the orthogonal axis to selectively position the printing position and the non-printing position so that printing and maintenance can be performed. Therefore, it is not necessary to secure a large empty space for maintenance in the width direction of the printing surface, and the relative positioning between the ink jet nozzles for each color and the printing surface when returning to the printing position can be performed accurately. As a result, the inkjet nozzles for each color can be quickly and reliably maintained while achieving downsizing and high quality printing.

According to the second aspect of the present invention, the slider for supporting the ink jet nozzles for each color is formed so as to be able to be driven up and down along the guide rails by using the electric force as the elevating means, and the spontaneous drop of the slider during power failure is suppressed. Since the brake means is provided, the position of the slider (printing position, non-printing position) can be switched quickly and accurately. In addition, it is possible to prevent the slider from rapidly dropping and stopping at the time of power failure and the inkjet nozzles for each color from being damaged by an excessive impact force. Therefore, the same effects as those of the first aspect of the invention can be obtained, and furthermore, maintenance can be performed more quickly and smoothly, and further higher printing speed, higher quality, and improved durability can be achieved.

According to the third aspect of the present invention, since the attitude stabilizing means for stabilizing the attitude of each color ink jet nozzle with respect to the guide rail is provided, the spray condition of each color ink jet nozzle and the attitude at the time of maintenance are always constant. As a result, the same effects as those of the second aspect of the invention can be obtained, printing can be performed with higher quality, and maintenance can be performed smoothly and reliably.

According to the fourth aspect of the present invention, the lifting drive means uses a general motor as a power source utilizing electric power, and the brake force applying means switches between a state in which braking force can be applied and a state in which braking force cannot be applied. Since electric power is used in the same manner as the lifting drive means, the same effects as in the inventions of claims 2 and 3 can be obtained, and further simplification of the configuration and expansion of applicability are achieved. Can be.

[Brief description of the drawings]

FIG. 1 is a diagram for describing an embodiment of the present invention.

FIG. 2 is a view for explaining a lifting unit.

FIG. 3 is a diagram for explaining a maintenance unit.

FIG. 4 is a view for explaining a positional relationship between a maintenance unit and each ink jet nozzle.

FIG. 5 is also a diagram for explaining the overall configuration.

FIG. 6 is a view for explaining a conventional general inkjet printer.

FIG. 7 is a diagram for explaining a previously proposed inkjet printer.

[Explanation of symbols]

 Reference Signs List 10 drum (rotating body) 11 outer peripheral surface 200 nozzle unit (print head) for each color 207 inkjet nozzle for each color 300 elevating unit 301 guide rail 309 nozzle support member 309F fixed frame 311 slider 315 support shaft 321 elevating driving unit 322 motor 323 power conversion Means 331 Attitude stabilizing means 332 Shaft member 335 Roller 341 Brake means 342 Brake force applying means 346 State switching means

Claims (4)

[Claims] An ink jet nozzle for each color is formed using an elevating means so as to be able to ascend and descend between a printing position and a non-printing position in a direction of an orthogonal axis orthogonal to a printing surface. An inkjet printer formed so as to be capable of printing on a printing surface and performing maintenance of inkjet nozzles for each color at a non-printing position. 2. A guide rail in which said lifting means is parallel to said orthogonal axis and is set up on one side centering on said orthogonal axis in the longitudinal direction of said printing surface, and a slider mounted on said guide rail so as to be able to move up and down. And lifting means for driving the slider up and down using electric force, and brake means for suppressing the natural fall of the slider when the lifting and lowering drive means cannot be driven up and down due to a power failure. Item 1. An inkjet printer according to Item 1. 3. The ink jet nozzle for each color is rotatably mounted on the slider around a fulcrum, and engages with the slider, and resists the rotation of the ink jet nozzle for each color by its own weight. 3. The ink jet printer according to claim 2, further comprising a posture stabilizing means for stabilizing the posture of the ink jet nozzle with respect to the guide rail. 4. The lift drive means comprises a motor and a power conversion means for converting the rotational power of the motor into a lift power of the slider, and the brake means works with the motor or the power conversion means to generate a braking force. 3. A braking force applying means, comprising: a braking force applying means capable of applying the braking force; and a state switching means for switching the braking force applying means to a state in which the braking force cannot be applied and a state in which the braking force can be applied in the event of a power failure. Or the inkjet printer according to claim 3.